Arc Plasma Numerical Simulation Of Considering Metal Vapor Atmosphere

When we use the welding method of inert gas as protective gas,such as MIG welding,protective gas will become the arc plasma by ionizing.In this process,there are must a lot of metal vapor enter the arc plasma,which influences the character of arc plasma.If we don't consider the metal vapor,there are some deviations when we learn the arc temperature field and a series of physical fields.Even which lead to low efficiency and the poor quality of welding products.Because of arc plasma temperature is too high and forming process is extremely complex,and through the test method to observe and measure are very difficult.Therefore,in order to further study this subject,this paper will explore the behavior characteristics of arc plasma under considering metal atmosphere by computer numerical simulation technology.This will help to better select arc welding parameters and stable welding process,ensuring the welding quality.Firstly,author will see metal inert-gas welding(MIG)as the main research carrier,regardless of physical and chemical process of droplet transition.We already master and apply the continuity equation,momentum conservation equation,energy conservation equation and the electromagnetic field equation and composition of transport equation equations.After in deep understanding of plasma arc principle,composition and mechanism,author apply the simulation software of FLUENT,then building a two-dimensional axisymmetric model under considering metal vapor arc plasma.In addition,We also simplified the cathode,and choose the reasonable calculation method to calculate.Secondly,author will consider two aspects to research the topic.On the one hand,we calculate the typical arc plasma's temperature field without considering of metal vapor,and also calculate the arc plasma's temperature field that consider metal vapor without theradiation energy loss.After comparison,the author draws a conclusion:metal vapor not only lead to significantly shrink the arc shape,but also the arc temperature become more low strongly.So when we research the properties of welding arc,we must consider the metal vapor.On the other hand,under the premise of considering the metal vapor atmosphere,we calculate the arc plasma's temperature field that consider metal vapor with the radiation energy loss.Then compare with the without radiation energy's arc through the physical field(temperature,electric potential,current density and mole fraction of metal vapor).Then have a conclusion: the temperature of the arc plasma with radiation energy loss can be further decline and the arc shape will be further shrunken;The arc voltage and current peak and overall range are increased;Fe vapor distribution is more extensive.So when the metal enter the arc,the radiation energy will be must considered.Finally,the author study the effects of welding current,metal vapor evaporation rate and protective gas flow rate on the arc plasma.Results show: when increase the welding current,the arc temperature will rise and the shape will shrink and radiation energy loss will exacerbate;increasing the evaporation rate of metal vapor will lead to the arc temperature rise and the shape shrink and radiation energy loss exacerbated;Low flow rate,increasing the inert gas flow rate,the arc temperature slightly higher,shape will shrink and radiation energy loss will exacerbate.The degree of three welding parameters of influence on arc become more and more weak.